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• Spirochetes


  "Spiro" = "coiled," and "chaete" = "hair"
• Spirochetes

  • Long, slender, helically curved, gram-negative bacilli
  • With the unusual morphologic features of axial fibrils and an outer sheath
  • Fibrils, or axial filaments, are flagella-like organelles that wrap around the bacteria's cell walls, are enclosed within the outer sheath, and facilitate motility of the organisms
  • The protoplasmic cylinder gyrates around the fibrils, causing bacterial movement to appear as a corkscrewlike winding

  
• Spirochetes

  • Can be visualized only by: a. darkfield or phase microscopy, b. silver impregnation, and c. immunohistochemical stains in tissue sections
  • Facultatively anaerobic or aerobic
  • Multiply by asexual transverse binary fission
  • Motile: Axial fibrils - flagella-like organelles

  
• Genera of spirochetes that cause human disease

  • Treponema
  • Borrelia
  • Leptospira

  
• Diagnosis often relies upon the demonstration of a patient's serologic response to the offending agent
• Three sequential phenomena in human disease caused by spirochetes

  • Early, local proliferation of the organisms at the site of inoculation
  • Spirochetemia with systemic dissemination
  • Persistence of small numbers of microbes at various, often immune, "privileged" sites
• Varying Characteristics of the Genera Within the Order Spirochaetales

  • Number of axial fibrils or periplasmic flagella
  • Number of insertion disks
  • Biochemical and Metabolic features

  
• Treponema

  Genus name came from the Greek word: "turning thread" - "trepein" means to turn and "nēma" means thread
• Treponema


  • Microaerophilic
  • Best observed with dark-field microscopy or phase-contrast microscopy
  • Thin, spiral organisms (4 to 14 spirals/organism) with three axial filaments and one insertion disk
  • Cells are pointed and covered with a sheath
  • Positive corkscrew motility

  
• Species of Treponema responsible for disease in humans

  • T. pallidum
  • T. carateum

  
• Subspecies of T. pallidum

  • T. pallidum subspecie pallidum
  • T. pallidum subspecie pertenue
  • T. pallidum subspecie endemicum
• Treponema species are serologically & morphologically indistinguishable, but are differentiated by type of lesions produced

  
• Dark Field Microscopy (DFM)

  Most definite & earliest means of diagnosis for Treponema, as they are very hard to stain and best observed by DFM<|>DFM can be positive several weeks before a positive serologic test
• Procedure for Dark Field Microscopy

  1. Lesion cleansed with sterile H2O then gently abraded

  2. Apply pressure & collect exudates

  3. DFM not recommended for oral lesions

  4. Confusion with commensal treponemes in the mouth (T. denticola)

  5. DFM should be done 10 minutes after acquiring the sample
• FTA-ABS (fluorescent treponemal antibody absorption) test

  Positive test for antibody response in patient with syphilis
• T. pallidum subspecie pallidum

  • Disease of blood vessels (remarkable tropism (attraction) to arterioles; infection ultimately leads to endarteritis (inflammation of the lining of arteries)
  • Non culturable in artificial medium, maintained in testicular chancres of rabbit
  • Causes SYPHILIS, also known as Lues venera, Italian disease or French disease, Great pox or evil pox

  
• Modes of Transmission for T. pallidum subspecie pallidum

  • Sexual
  • Parenteral
  • Transplacental (Mother-to-fetus)
• T. pallidum subspecie pallidum


  • Close-coiled, thin, regular spiral organism, 6-15μm in length, consisting of 10 – 13 coils and three fibrils/periplasmic flagella
  • Thin, tightly wound, rigid, spiral organism
  • Sluggish motility, exhibits little flexibility and does not move from place to place
• Stages of Syphilis

  • Primary Stage
  • Secondary Stage
  • Latent Stage
  • Tertiary Stage
• Primary Stage of Syphilis

  • Extremely infectious, because the lesion contains a large number of organisms
  • Develops after 10 – 90 days (Ave. 21 days) after infection
  • Hard chancre appear at site of entrance, which persists for 1-5 weeks
  • Lesions: Hard chancre or Hunterian chancre - single, firm, painless, non-itchy skin ulceration with a clean base and sharp borders between 0.3 & 3.0 cm in size; evolves from a macule to a papule, & finally to an erosion/ ulcer
  • No systemic signs or symptoms evident
• Secondary Stage of Syphilis


  • Patient usually seeks medical attention
  • Manifestations: rashes and lymphadenopathy with such as fever, weight loss, malaise, and loss of appetite
  • Highly infectious state, again because large numbers of spirochetes are present
  • 12 weeks after the appearance of the 1° chancre
  • Lesions: CONDYLOMATA LATA - Rashes that become maculopapular or postural and form flat, whitish, wart-like lesions particularly in the mucous membranes
  • Bloodstream dissemination - Generalized rash on trunk and extremities

  
• Latent Stage of Syphilis


  • Period in which the disease becomes subclinical but not dormant
  • Patient non-infectious
  • Occurs within more than a year of infection
  • May last for years or for the rest of the patient's life
  • No lesions, absence of signs & symptoms
• Tertiary Stage of Syphilis

  • Tissue-destructive phase
  • Lesions: Gummatas - soft, tumor-like balls of inflammation which may vary considerably in size
  • Seen 10-25 years after 1° stage
  • Gummas can be found in the CNS (Neurosyphillis), Cardiovascular system (aortic aneurysm), and Eyes (blindness)
• Three Manifestations of Tertiary Stage

  • Gummatous Syphilis
  • Cardiovascular Syphilis
  • Neurosyphilis (CNS Syphilis)
• Congenital syphilis

  • Hutchinson triad (deafness, blindness, notched peg-shaped teeth)
  • Poor bone formation may result, such as "saber shin" bowing of the tibia and the "bull dog" appearance of a deformed maxilla
• Lab Diagnosis for syphilis: Serologic tests only!
• Microscopic Examination

  1. Direct microscopic examination of exudates - Recommended

  2. Diagnostic for Primary Syphilis - Demonstration of motile treponemes from the chancre specimen

  3. Definitive test: DFM for motility

  4. Stains: Levaditi's Stain and Fontana-Tribondeau stains

  
• Serodiagnosis

  • RPR (Rapid Plasma Reagin)
  • VDRL (Venereal Disease Research Laboratory)
• Molecular Tests

  • Polymerase Chain Reaction - Used for neurosyphilis detection (AIDS patients)
  • Western blot - Used for the detection of congenital syphilis
• • RPR does not require the heating of the serum and is not recommended for CSF
  • VDRL is recommended for the diagnosis of neurosyphilis using CSF specimens
  • Reagents for the VDRL must be freshly prepared and the patient's serum must be heated at 56˚C for 30 minutes (complement inactivation)
• T. pallidum subspecie pertenue

  • Causes YAWS - Chronic skin & bone disease of the tropics, also called FRAMBESIA TROPICA, PIAN, PARANGI, PARU & BUBA
  • Most prevalent of the Nonvenereal treponematoses
  • Mode of Transmission: direct contact with skin lesions (Fambresia)
  • Approximately 10% develop late yaws, which shows irreversible, destructive lesions of bone, cartilage, soft tissue, and the skin
• T. pallidum subspecie endemicum

  • Causes BEJEL: Endemic NonVenereal Endemic Syphilis
  • Mode of Transmission: direct contact, sharing of eating or drinking utensils
  • Lesions: Primary - oral cavity, Secondary - oral mucosa, Tertiary - skin/bones/nasopharynx
  • Late stage is characterized by tissue destruction of the skin, bones, and cartilage

  
• Treponema carateum

  • Causes PINTA - an ulcerative skin disease of Central & South America, also CARATE, MAL DE PINTO, AZUL
  • Lesions: PINTID - scaly psoriasiform plaques commonly occur in hands, feet and scalp, skin appears to be the only organ affected in this disease

  
• Treponema species that are normal microbiota

  • Treponema denticola
  • Treponema socranski
  • Treponema pectinovorum
• Acute necrotizing ulcerative gingivitis, also known as Vincent disease, is a destructive lesion of the gums caused by normal oral treponemes
• Treponemes cannot be cultivated, so antimicrobial susceptibility testing is not performed. Penicillin G is the drug of choice for all treponemal infections.
• Borrelia

  Blood Spirochetes - Flexible twisted organisms resembling a stretched spiral
• Borrelia

  • Vectors: lice or ticks
  • Slow-growing spirochetes
  • Multiply by binary fission
  • Actively motile - Contain 15 – 20 axial filaments and two insertion disks, 3 to 10 loose coils
• Borrelia Clades


  A group of organisms, such as a species, whose members share a common ancestor
• CARATE, MAL DE PINTO, AZUL

  Lesions: PINTID